The invention relates to a ramp voltage generator circuit and, more particularly, to a linear ramp voltage generator circuit comprising an electronic switch and a ramp circuit which utilizes an operational amplifier having positive and negative feedback to provide an output voltage which is linear with time.
Ramp voltage generator circuits are used to provide ramp voltages which increase at a predetermined linear rate. Such ramp voltages may be used to externally control, for example, the horizontal deflection of an oscilloscope, or a plotter. The ramp circuitry that is currently known requires a plurality of active components, i.e., components which require an applied voltage. Such a ramp circuit is shown in U.S. Pat. No. 4,029,972, issued to Fox et al. on June 14, 1977. The Fox et al. ramping circuit utilizes two operational amplifiers to provide a ramp voltage from a square wave input. As the number of active components in a ramping circuit increase, the power requirements of the circuit also increase, and the usefulness of the circuit in low power applications, such as in battery operated equipment, decreases. Thus, it is desirable that the ramp circuit of a ramp voltage generator has a minimum number of active components while providing a linear output.
It is also desirable that the electronic switch portion of the ramp voltage generator be activated and reset manually. Such manual operation is useful where test equipment is to be externally controlled, and data is to be recorded.